1. Field of the Invention
This invention relates to a washing apparatus for filter presses and more particularly it relates to an apparatus for washing filter cloths being pulled by filter plates as the latter are separated one by one toward a movable end plate upon completion of filtration or for washing the filter plate surfaces after having the filter cloth removed therefrom.
2. Description of the Prior Art
Filter washing means using a horizontal spray pipe adapted to be vertically moved between opened filter plates by a pantograph mechanism is known, as disclosed, e.g., in Japanese Patent Publication No. 35161/1980 and U. K. Patent No. 2,046,117.
In the former, a bushing 4 fixedly fitted in a bevel gear 3 is formed with an internal thread, while a threaded bar 6 threadedly engaged with said internal thread of the bushing is vertically moved by the rotation of a geared motor 1 to thereby effect vertical movement of filter washing means 19 which comprises a spray pipe connected to the lower end of a pantograph 8. With this arrangement, however, when said filter washing means is pulled upwardly of the filter plates, the screw shaft, or bar, threadedly engaged with the bushing projects high above the geared motor and thus has the disadvantage of requiring a high space above the filter press.
On the other hand, in U. K. Patent No. 2,046,117, one link of a link connection for a pantograph is used as a washing liquid pipe and the ends of the washing liquid pipe are connected by liquid seal joints. The middle of each washing liquid pipe is pivoted to a bar which is the other element of the pantograph. The washing liquid pipe together with the bar performs pantograph motion. The lowermost element of the pantograph is a spray pipe having a number of liquid spraying holes, with a link connected to one end thereof which link causes the spray pipe to ascend or descend in a horizontal posture. However, since the rod of the actuator is obliquely connected at a position considerably spaced away from the middle of the link width of the pantograph, the pantograph tends to sway. Another disadvantage of this arrangement is that leakage of liquid can easily occur since the perfectness of the leakage preventive seat construction at the opposite end of the washing liquid pipe in the pantograph can hardly be maintained.